I wonder if you could fill the head of the screws with RTV silicone or something similar so the heads of the screws don't fill with crud making them unable to be removed, then if/when you want to remove the screws you can pull the RTV out. All I can think of is the screws that hold the plastic trim on a vehicle over the top of the rockers and how much of a pain in the ass those are to remove after they fill with crud.